University of Arizona – Lithography

Stone Etch Methods

Before etching the stone, always rosin and talc the image first. Rosin is primarily used as an acid resist. Talc serves to harden the drawing materials while overcoming their tendencies to repel the water in the gum. It is recommended to apply talc first when etching the original drawing, but to apply rosin first when etching an inked image.

Applying Rosin and Talc

The Single Strength Method

This is the simplest and most common approach to etching a stone image. With this approach, one etch solution is used to treat all areas of the image. This method is recommended for drawings executed with #'s 2, 3, & 4 crayons, drawing containing uniform grease levels, and other types of work where the desire for simplicity outweighs the desire for high image retention. Refer to the Stone Etch Table for determing the appropriate strengths. Here is how the Single Strength Method works:

  1. Quickly apply the etch, liberally covering all areas of the stone. It is usually best to start in a non-image area or margin and to spread it from there.

  2. Massage the etch into the stone for 2-3 minutes.

  3. While the etch is still loose and runny, quickly buff the surface of the stone with cheesecloth's down to a very thin and even coat.

  4. It is best to store the stone and wait 24 hours before proceeding with the next step, but you can proceed as soon as 15 minutes after the etch is dry

Applying the single strength etch

The Wet-on-Wet Method (Multiple Strengths)

This is a moderately complex method. With this approach, several etch solutions of different strengths are applied simultaneously. It is recommended for drawings where a variety of grease levels are present and absolute precision is either impossible or unnecessary.

  1. Paint the different etches onto the appropriate areas of the image, attempting to move quickly enough so that none of the painted areas have time to dry. Cover all areas of the stone. Freshen the respective areas with new etch, working them around with the brush and keeping them wet. Avoid overlapping image areas with etches too strong for them to withstand. Do this for 2-5 minutes.

  2. Blot up excessive pools of the stronger etches with a gum sponge.

  3. If all of the etches are still loose and runny, quickly buff the surface of the stone with cheesecloth's down to a very thin and even coat. Otherwise, pour on enough of the weakest etch so that all etches will be re-dissolved and then buff.

  4. It is best to store the stone and wait 24 hours before proceeding with the next step, but you can proceed as soon as 15 minutes after the buffed etch is dry.

The Wet-on-Dry Method (Multiple Strengths)

This is the most complex and painstaking method. It is recommended for all drawings where a variety of grease levels is present and absolute precision is desired.

  1. Begin by etching the entire stone with the weakest of the etches to be used (usually straight gum) as described under steps 1-4 of the "Single Etch Method."

  2. Carefully work on top of the dried weak etch. Paint the different etches onto the appropriate areas of the image. Apply etches one at a time, liberally, refreshing them and working them with the brush as you go. Take as much time as you need to repeatedly, but precisely, brush the respective areas.

  3. After each etch has been on the stone for several minutes, carefully blot it so it is not too thick. Then, allow it to dry. Do all areas this way.

  4. After the entire image has been treated, allow the stone to dry and wait 15-30 minutes more.

  5. Next, massage the entire surface with a solution of straight gum until all areas have become dissolved, and then buff to a very thin and even coat.

  6. It is best to store the stone and wait 24 hours before proceeding with the next step, but you can proceed as soon as 15 minutes after the buffed etch is dry.